HS2 engineers have installed the final roof segment on the 700-metre-long Burton Green tunnel - illustrating the progress being made on the West Midlands section of Britain’s new railway.
The 16-metre-wide twin-box-shaped tunnel will carry high-speed trains beneath the village of Burton Green, near Kenilworth. The internal wall separates trains travelling north to Birmingham, Manchester and Scotland, and south towards HS2’s two London stations in Old Oak Common and Euston.
Now structurally complete, engineers and ecologists will turn their attention towards the tunnel’s 500-metre-long ‘green roof’, to ensure the structure blends seamlessly into the natural landscape, with ample green space above for local communities to enjoy.
Doug Barnett, Senior Project Manager for HS2 Ltd, said:
“With the main civil engineering complete, thanks to the hard work and dedication of the 150-strong team on the ground, we can now begin the next phase of this exciting project.
We look forward to working with local communities to bring the bold design vision for Burton Green tunnel to life, maximising the potential of this new green space.”
A strong focus has been placed on connectivity and access to the new green space for local communities – linking both sides of the village of Burton Green. Once fully complete, the Kenilworth Greenway will be reinstated close to its original alignment. It will run above the new tunnel to provide a link from Balsall Common to Kenilworth, via Burton Green, for walkers, cyclists and horse-riders.
Tim Akers, Design Manager from the Mott MacDonald/SYSTRA Design Joint Venture, said:
“A range of techniques were incorporated into the design to enable construction through this narrow corridor within the village. The end result will be a railway within a landscape, where the original character of the Kenilworth Greenway and ecological connectivity to the wider landscape are restored over the buried tunnel.”
Excavated material from the tunnel is currently being reused for wider landscaping works, in line with HS2’s sustainability commitments. Large-scale planting of native trees and shrubs will provide biodiverse habitats for wildlife and re-establish vegetated connections to Black Waste Wood and Little Poors Wood.
HS2’s construction partner, Balfour Beatty VINCI (BBV), is working closely with community groups and schools to explore ways in which they can enhance the Greenway experience whilst celebrating the area's unique landscape, ecology and heritage.
Rupert Blake, Project Manager for BBV, said:
“The structural completion of Burton Green tunnel is a huge moment for BBV and our supply chain partners, who’ve worked tirelessly over the last five years to get us here.
“A range of construction techniques have been used to deliver this complex engineering project, showcasing the team’s skill, expertise and resilience. The next step is to install a 500-metre green roof on top of the structure, so it integrates into the natural landscape."
BBV’s civil engineering team is now working on the final elements of the tunnel, including the escape walkway to the south of the tunnel, and the application of fire-proof protection to the upper tunnel walls.
As the tunnel runs underneath Burton Green village, the team had to carefully plan the whole construction schedule to ensure vehicle and pedestrian access could be maintained.
Cromwell Lane, which links both sides of the village, was temporarily diverted during the construction. In October, following the completion of vital utilities works, it will reopen on its original realignment.
Recognising its significance to local communities, throughout the construction phase HS2 also created a temporary route for the Kenilworth Greenway. This starts at the site of the Burton Green Village Hall and then follows the existing field boundaries linking with Berkswell Station in the northwest.
Galldris Group were the main civils subcontractor and have played a key role in the delivery of Burton Green tunnel and its associated retaining structures, with a direct workforce of over 100 people based on-site.
Ibrahim Arshad, Senior Project Manager from Galldris Group, said:
“From start to finish, we have provided engineering expertise, detailed planning and self-delivery capabilities to safely deliver this complex section of HS2.
“Working collaboratively with Balfour Beatty VINCI, the design joint venture and the wider supply chain, we are proud to have contributed to the structural completion of one of HS2's most significant green tunnels.”
Burton Green tunnel is one of five ‘green tunnels’ being built on the route of the railway. The cut and cover design means they are shallower than deep twin-bore tunnels, and each tunnel will be finished with trees, plants and shrubs on top, helping them blend into the landscape. The four other green tunnels are Copthall in outer London, Wendover in Buckinghamshire and Chipping Warden and Greatworth, both in Northamptonshire.
HS2 Ltd CEO Mark Wild is now leading a comprehensive reset of the project to ensure that it is delivered as efficiently as possible and for the lowest reasonable cost. The 140-mile railway is now at a peak construction between London and the West Midlands, with improvements in productivity made over the last year and key milestones now being reached across the route. This includes the recent successful operation to push HS2’s tallest viaduct into place in Birmingham and the completion of piling works on the city’s Curzon Street station.
